Lwambo N J, Upatham E S, Kruatrachue M, Viyanant V
Department of Biology, Faculty of Science, Mahidol University, Bangkok, Thailand.
Southeast Asian J Trop Med Public Health. 1987 Jun;18(2):156-65.
The infectivity of miracidia of the Saudi Arabian isolate of S. mansoni in Bi. arabica was found to be influenced by such factors as miracidial dose, water temperature and salinity. The pre-patent period of S. mansoni in Bi. arabica was 30 to 33 days. Miracidial dose had no effect on the mortality of snails during the pre-patent period. The infection rate increased as the miracidial dose was increased. However, cercarial production was highest in snails exposed to 1 miracidium each and decreased as the miracidial dose was increased. Water temperature during exposure had an influence on the mortality, infection rate and cercarial production in Bi. arabica exposed to S. mansoni miracidia. The infection rate was highest in snails exposed at 28 degrees and 34 degrees C. No infection of Bi. arabica occurred at the temperature of 10 degrees C. The number of cercariae per snail per day was highest in snails exposed to miracidia at 34 degrees C. It was demonstrated that salinity had an influence on the infection of Bi. arabica with miracidia of S. mansoni. The infection rate in snails decreased as the salinity increased up to 4,500 mg/l, above which no infection occurred. The daily pattern of cercarial emergence was rhythmic, whereby 94.7% of the total daily production was released within 6 h from infected Bi. arabica, with a peak between 11 a.m. and 1 p.m.
已发现，曼氏血吸虫沙特阿拉伯分离株的毛蚴对阿拉伯双脐螺的感染力受毛蚴剂量、水温及盐度等因素影响。曼氏血吸虫在阿拉伯双脐螺体内的潜伏期为30至33天。毛蚴剂量对潜伏期内螺的死亡率无影响。感染率随毛蚴剂量增加而升高。然而，每只螺暴露于1个毛蚴时尾蚴产量最高，且随毛蚴剂量增加而降低。暴露期间的水温对暴露于曼氏血吸虫毛蚴的阿拉伯双脐螺的死亡率、感染率及尾蚴产量有影响。暴露于28℃和34℃的螺感染率最高。在10℃时未出现阿拉伯双脐螺感染情况。每天每只螺的尾蚴数量在暴露于34℃毛蚴的螺中最高。结果表明，盐度对阿拉伯双脐螺感染曼氏血吸虫毛蚴有影响。螺的感染率随盐度增加至4500mg/l而降低，超过该盐度则无感染发生。尾蚴逸出的每日模式具有节律性，即每日总产出的94.7%在6小时内从受感染的阿拉伯双脐螺中释放，上午11点至下午1点之间达到高峰。
